Forums
Gaming Sites:
Holmes Basic forum on OD&D Discussion - highest traffic forum dedicated to Holmes Basic & my favorite place to discuss anything from this site
Classic D&D forum on Dragonsfoot - high traffic but covers all forms of Classic D&D
Holmes Basic forum on Knights & Knaves Alehouse - dedicated to Holmes Basic but low traffic
Classic D&D forum on OSRgaming - medium traffic, covers all forms of Classic D&D
Holmes Basic page at RPG Geek - has a forum for posting
Collecting Sites:
The Acaeum - high traffic
General Collecting (TSR) Forums - occasional Holmes Basic-related discussion
Tome of Treasures - low traffic
TSR Borderlands Keep forum - general TSR collecting discussion
Basic D&D modules research forum
Games Workshop editions research forum - includes UK Holmes Basic